One of the things I like about Mephisto is the asset management. Especially the way how you insert image URLs by dragging thumbnail from sidebar to content area. Frog CMS lacked easy way for inserting images (or any other files). Obvious thing to do was implement Mephisto style asset management as a plugin.
It is not one to one copy on how Mephisto does it. Instead of tagging assets you can categorize them by uploading to different folders. There is also extra pulldown to select which assets to show in sidebar while editing.